Approximate true-color view of the southern hemisphere of Uranus made from images acquired by the Voyager 2 spacecraft in January 1986.

Scientists have just confirmed what every third-grader has known for nearly 170 years* as irrefutable fact: Uranus smells like stinky farts.

Let the giggling commence.

First of all, I’m assuming you’re used to using the pronunciation “your-AY-nus,” which of course in English provides all sorts of opportunities for comedy. But if you use the other (and technically more correct) pronunciation “YER-ah-nus” then perhaps we can proceed with a modicum of dignity here.

Researchers have identified the chemical signature of hydrogen sulfide in the upper atmosphere of Uranus, the pale blue gas-enshrouded ice giant located between Saturn and Neptune.

Closer gaseous planets to the Sun Jupiter and Saturn don’t appear to have any detectable H2S in their upper atmospheres, but Uranus does. Given the long-standing fun kids (and adults) have had with the planet’s name, it seems fitting. But in actuality the confirmation of the compound’s presence really is a new discovery.

“We’ve strongly suspected that hydrogen sulfide gas was influencing the millimeter and radio spectrum of Uranus for some time, but we were unable to attribute the absorption needed to identify it positively. Now, that part of the puzzle is falling into place as well,” said Glenn Orton, one of the team’s researchers from NASA’s Jet Propulsion Laboratory in Pasadena, CA.

The findings were made using data acquired by the Near-Infrared Integral Field Spectrometer (NIFS) on the 8-meter Gemini North telescope on Maunakea in Hawai’i.

“This work is a strikingly innovative use of an instrument originally designed to study the explosive environments around huge black holes at the centers of distant galaxies,” said Chris Davis of the National Science Foundation, a leading funder of the Gemini telescope. “To use NIFS to solve a longstanding mystery in our own Solar System is a powerful extension of its use.”

It’s very likely that Neptune, located even further out than Uranus, also has hydrogen sulfide in its upper atmosphere…although it’s only speculation at this point. Both planets contain large amounts of hydrogen, helium, and methane in their atmospheres—the latter of which absorbs red wavelengths of light and gives them their bluish color. But methane to us is odorless…hydrogen sulfide is certainly not.

So if for any reason you were to stick your head in Uranus and take a deep breath (don’t forget our pronunciation lesson now) you would likely wonder who was responsible for the smell…that is, before your face froze off in the -300ºF temperatures and you suffocated from the lack of any breathable oxygen.

Then again, it might be a welcome end were you to find yourself stuck on a stinky planet four times the size of Earth.

*When William Herschel discovered Uranus in 1781 he named it “the Georgium Sidus” (the Georgian Planet) in honor of King George III. It wasn’t until about 1850 that the name Uranus—the Greek god of the sky—was in common use. (Source)

Everyone’s heard of Jupiter’s four most famous moons Europa, Io, Callisto, and Ganymede—we’ve known about them for over 400 years, thanks to Galileo—but giant Jupiter has many more moons than that. To date there are thought to be 69 natural satellites orbiting Jupiter. 53 are officially named, while 16 are awaiting further confirmation. So you’d be forgiven for not being immediately familiar with all of them…it’s a big Jovian family!

The little world seen above is one of Jupiter’s smaller and lesser-known satellites and it holds a particular distinction. It’s called Metis (pronounced like “meet” in the present tense, not “met” in the past) and it’s only about 37 miles across and 21 miles high. It is the closest moon to Jupiter, orbiting within the planet’s main ring (yes, Jupiter has rings) at a distance of about 80,000 miles. It’s also Jupiter’s speediest moon—at 70,500 mph it completes a single orbit in just over 7 hours. That’s almost three hours less than a Jovian day!

The image above was captured by NASA’s Galileo spacecraft on November 6, 1997, two years into its 8 years in orbit at Jupiter. It’s a highly-upscaled version of a raw file I downloaded from NASA’s Planetary Data System (PDS) archive using SETI’s OPUS site. I’ve recently been looking into some raw data from older missions with the goal of processing better versions of things I had worked on in previous years using lower-quality preview JPEGs, and also finding some things I didn’t know about before. Metis is one of them!

Galileo wasn’t the first spacecraft to capture images of Metis; actually Voyager 1 was. The moon was discovered by JPL astronomer Stephen Synnott in data acquired by Voyager 1 in 1979 during its flyby of Jupiter. In March 4 of that year Metis was captured passing in front of Jupiter’s bands of swirling clouds…imagine its view!

The image below is a color-composite I assembled from Voyager 1 observations in red, green, and blue visible-light filters. 37-mile-wide Metis is a tiny speck near the lower right.

Color-composite of Metis and Jupiter from Voyager 1 in March 1979. (NASA/JPL/Jason Major)

Can you spot Metis? If not, here’s some help:

There are three other inner moons of Jupiter in addition to Metis, which is the closest—Adrastea (the smallest and the only other inner moon to orbit faster than a Jovian day), Amalthea (the largest and first-known), and Thebe (rhymes with Phoebe). All orbit between the rings and the orbit of Io, the innermost of the four Galilean moons.

]]>https://lightsinthedark.com/2018/04/03/meet-metis-jupiters-closest-quickest-moon/feed/55J. MajorAn Opportunity From Abovehttps://lightsinthedark.com/2018/03/09/an-opportunity-from-above-2/
https://lightsinthedark.com/2018/03/09/an-opportunity-from-above-2/#commentsFri, 09 Mar 2018 21:28:04 +0000http://lightsinthedark.com/?p=8950To commemorate the 12th anniversary of NASA’s Mars Reconnaissance Orbiter at Mars (March 10, 2006) and the still-roving Opportunity, below is an edited version of an article I wrote back in 2011 showing Opportunity imaged by MRO’s HiRISE camera.

NASA’s Opportunity rover on the edge of Santa Maria crater imaged by HiRISE on March 1, 2011.

The eye in the sky sees all…especially when that eye is the HiRISE camera on the Mars Reconnaissance Orbiter! Here’s an image of a crater known as Santa Maria, taken from over 150 miles above the Martian surface by the MRO…and if you look carefully at the lower right portion of the crater rim you can see a small grey object that casts a bit of a shadow. That’s the rover Opportunity, which has been investigating the area around Santa Maria for the past several months and was using its robotic arm to take close-up shots of a small nearby rock when the image above was acquired.

I wonder if she got the feeling that she was being watched.

Enlarged detail of Opportunity in the HiRISE image.

On the left side of the image the rover’s tracks can be seen as a faint reddish line extending off frame. (For a full-size view of the area click here...the tracks are more obvious there.)

Opportunity is currently the only active robotic explorer on the surface of Mars. (Note: this was written a year and a half before Curiosity landed!) It has been steadily traveling across the relatively flat Meridiani Plains region toward the much larger Endeavour Crater, stopping occasionally to investigate interesting features such as rock outcroppings, standing meteorites and various craters – such as Santa Maria.

Opportunity completed its three-month prime mission on Mars in April 2004 and has been working extended missions since then. The Mars Reconnaissance Orbiter, which arrived at Mars on March 10, 2006, has also completed its prime mission and is currently operating an extended mission.

Opportunity’s sister rover, Spirit, fell silent over eleven months ago (now nearly eight years ago) after becoming stuck in loose sand and losing its ability to maneuver. MER team engineers have been trying to regain contact with Spirit ever since but no signal has been detected as of yet. Opportunity, on the other hand, is fully operational and in good roving form. Not bad for a little ‘bot that was originally intended for a 90-day mission! She’s making us proud, working away all alone on Mars.

Well, not alone…she’s got a friend in the sky above who keeps a good eye on her.

Learn more about Mars Reconnaissance Orbiter here, the HiRISE camera operated by the University of Arizona here, and Opportunity here.

P.S. Be sure to check out Stu Atkinson’s The Road to Endeavour for updates on Opportunity’s progress and the latest images!

]]>https://lightsinthedark.com/2018/03/09/an-opportunity-from-above-2/feed/2J. Major